Objectives. We sought to describe the prevalence, characteristics, and mental health problems of children who experience perceived racial/ethnic discrimination. Methods. We analyzed cross-sectional data from a study of 5147 fifth-grade students and their parents from public schools in 3 US metropolitan areas. We used multivariate logistic regression (overall and stratified by race/ethnicity) to examine the associations of sociodemographic factors and mental health problems with perceived racial/ethnic discrimination. Results. Fifteen percent of children reported perceived racial/ethnic discrimination, with 80% reporting that discrimination occurred at school. A greater percentage of Black (20%), Hispanic (15%), and other (16%) children reported perceived racial/ethnic discrimination compared with White (7%) children. Children who reported perceived racial/ethnic discrimination were more likely to have symptoms of each of the 4 mental health conditions included in the analysis: depression, attention deficit hyperactivity disorder, oppositional defi-ant disorder, and conduct disorder. An association between perceived racial/ ethnic discrimination and depressive symptoms was found for Black, Hispanic, and other children but not for White children. Conclusions. Perceived racial/ethnic discrimination is not an uncommon experience among fifth-grade students and may be associated with a variety of mental health disorders.